1. Field of the Invention
This disclosure relates to an organic electro-luminescence display device adapted to reduce electric power consumption by lowering the level of a supply voltage VDD, which is applied to a driver IC (integrated circuit) in an emission interval, below that of the supply voltage which is applied to the driver IC in a non-emission interval.
2. Discussion of the Related Art
As the information society grows, display devices capable of displaying information have been widely developed. These display devices include liquid crystal display (LCD) devices, organic electro-luminescence display (OLED) devices, plasma display devices, and field emission display devices.
Among the above display devices, OLED devices are self-luminescent display devices which electrically excite a fluorescent organic-compound to emit light. Such OLED devices have several desirable features such as a low driving voltage, a thin size, and so on. Moreover, OLED devices have a wide viewing angle and a fast response time, both of which prevent the disadvantages found in LED devices. In view of these points, OLED devices have received a significant amount of attention as next-generation display devices.
An OLED device includes a plurality of pixels arranged in a matrix. Each of the pixels includes a switching transistor, a storage capacitor, a drive transistor, and an organic light emission diode (OLED).
A data voltage is applied to the drive transistor by a switching operation of the switching transistor. The drive transistor derives a driving electric current from the data voltage. The OLED emits light corresponding to the driving electric current. The storage capacitor maintains the data voltage during one frame period. The switching transistor and the drive transistor are elements which increase the quantity of electric current as the temperature rises. The OLED is an element which emits light in proportion to a quantity of electric current received.
The OLED device is divided into a panel displaying an image and a driving portion for driving the panel. The driving portion includes a gate driver for driving a plurality of gate lines arranged on the panel, and a data driver for driving a plurality of data lines arranged on the panel. The driving portion can further include a timing controller for controlling the timing of both the gate driver and the data driver. Also, the driving portion can include a power supplier which generates a supply voltage VDD using an input voltage applied from an external power supply unit. The supply voltage VDD is used to drive the gate driver, the data driver, and the timing controller.
The supply voltage VDD generated in the power supplier usually maintains a constant level regardless of whether the OLED device is in an emitting interval or a non-emitting interval. Due to this, the electric power consumption of the power supplier increases. Furthermore, the electric power consumption of the OLED device which includes this power supplier increases.